1. Field of the Invention
This invention relates to replaceable ink supplies for ink recording devices and particularly to that type of supply which includes a flexible ink container disposed in a housing which includes a means temporarily increasing the pressure on the ink supply.
2. Description of the Prior Art
In ink recording devices or printers, a common arrangement is to utilize a recording head which moves along a recording carrier such as a paper, the recording head being supplied with a recording fluid (ink) from a supply bottle by means of an ink supply system. The recording head may be a mosaic recording head in which a plurality of piezoelectrically operated ink jet nozzles are arranged. It has been known to supply the recording head with ink automatically due to the contractions which take place in the inking nozzles of the recording head upon actuation of the individual nozzles. Due to the physical principles involved in the supplying of ink to the nozzles, it is critically important that air be eliminated from the ink supply system. In order to eliminate such air, it has been proposed to provide means within the ink supply system which allow the pressure on the ink supply reservoir, or ink source, to be momentarily raised so as to surge ink through the ink supply channels and the jet nozzles in order that the channels and nozzles will be flushed with the ink forcing all air from the recording head. One known system incorporates a plunger supported on a spring element, which may be a bellow spring, in such a manner that the plunger can be pressed against a flexible ink container which is received in a tub shaped recess of an ink supply housing.
It is, however, possible in the known systems for the flexible container to suddenly spring a leak. Such leaks can occur either through a defective area of the flexible ink container or because of inadvertent perforation. In such an instance the ink contained can escape from the container into the tub shaped recess of the housing which receives the flexible ink container. If pressure is exerted on the plunger, the ink will be forced out of the recess, and, in the process, can soil the operator as well as the associated equipment.
It would therefore be an improvement in the art if an ink supply device could be provided which allows a momentary pressure increased to be imparted to the ink supply for ink flushing of the recorder head but which is constructed such that even if the flexible ink container is perforated that no ink will escape from the recess receiving the flexible container to the exterior of the device. Further, it would be advanced in the art to provide such a device which, even when pressure is being applied by an operator, will insure that the ink from a burst or perforated ink container will not be directed at the operator and will not soil surrounding areas of the equipment. Moreover, it would be a further advance in the art if such a device could be produced simply and economically.